Hippocampal abnormalities in amnesic patients revealed by high-resolution magnetic resonance imaging

Article Abstract:

High-resonance magnetic imaging allows visualization or imaging of parts of the body by measuring the degree of absorption of radio waves by the nuclei of cells in the body. This advance in technology has allowed the visualization of parts of the body that could not be readily examined before. Using high-resonance magnetic imaging, the structures and connections of the hippocampus section of the brain, used in memory, were studied. The anatomical dimensions of different parts of the hippocampus were compared in three patients with memory impairment or amnesia, and four normal control subjects. No difference in the size of the temporal lobes of the hippocampus was measurable between the two groups, in contrast to the area of hippocampal formation, which was markedly reduced in memory-loss patients relative to controls. The area was 49 percent of the size of that of the controls. Damage to the hippocampal formation is also seen in patients with Alzheimer's disease, who suffer from memory impairment. The lateral ventricles were somewhat larger in the patients with memory impairment, but the differences were not significant. The area around the hippocampus, the parahippocampal gyrus, was smaller in one patient, but the same as the controls in the other two patients. Two of the three patients had discrete areas of abnormality located within the striatum, a collection of cell bodies deep within the brain, indicative of other disorders such as ischemia (reduced oxygen to the brain) or infarction (dead tissue due to lack of oxygen). Locating abnormalities in the brains of patients with memory loss is the first step in understanding the mechanisms of how memory works. High-resolution magnetic resonance imaging can be used as a diagnostic tool for diseases where memory loss occurs, such as Alzheimer's disease.

Analysis, Hypoxia, Anoxia, Magnetic resonance imaging, Memory, Disorders of, Memory disorders, Hippocampus (Brain), Basal ganglia, Amnesia

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Formation of amyloid-like fibrils in COS cells overexpressing part of the Alzheimer amyloid protein precursors

Article Abstract:

Alzheimer's disease is a degenerative condition of the central nervous system, leading to complete cognitive loss, and is characterized by the accumulation in the brain of fibrils (small fibers) composed of the protein amyloid. The mechanisms by which this substance is deposited in brain tissue are not known, and experiments were carried out to develop a satisfactory tissue-culture model of amyloid formation. Amyloid fibrils are composed mainly of B/A4 protein, which itself comes from a larger protein called amyloid protein precursor (APP). Abnormal processing of APP is thought to lead to the deposition of amyloid; hence, cDNA (genetic material) that coded for a region of APP considered likely to be aberrant in the Alzheimer protein (the C-terminal region) was inserted into cells of the COS lineage (a type of monkey kidney cell) in tissue culture. In a small number of the treated cells, deposits were found that, on examination with the electron microscope, had a structure similar to that of the amyloid of Alzheimer's disease. The deposits also appeared to react with an antibody made against the B/A4 protein. This is the first successful attempt to make amyloid fibril-like structures as a consequence of expression of the APP protein. (Consumer Summary produced by Reliance Medical Information, Inc.)

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Absence of aluminium in neuritic plaque cores in Alzheimer's disease

Article Abstract:

The lack of aluminum in neuritic plaque cores from people suffering from Alzheimer's disease (AD) deals a major blow to the theory that aluminum causes AD. Earlier etiological and epidemiological research had associated aluminum levels with AD. However, a new and highly sensitive technique, nuclear microscopy, was used to examine the plaque cores. The failure of this new method to detect aluminum suggests that the earlier findings resulted from contamination.

Health aspects, Aluminum in the body, Aluminum (Nutrient)

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